Calcareous nannofossils and sedimentary facies in the Upper Cretaceous Bozeş Formation (Southern Apuseni Mountains, Romania)

Abstract

Abstract. The lithology, sedimentology and biostratigraphy of the Bozeş Formation, which crop out in the SE Metaliferi Mountains (Apuseni Mts.) have been investigated in order to establish the age of the deposits and the depositional environment. The sedimentary structures and facies are interpreted as indicating a deep-water depositional environment, representing part of a submarine fan lobe. Three facies assemblages have been identified and described. Calcareous nannofossils were used to determine the age of the investigated deposits. The presence of Lucianorhabdus cayeuxii and Calculites obscurus indicates the CC17 biozone, while UC13 Zone is pointed out by the continuous occurrence of Arkhangelskiella cymbiformis and the absence of Broinsonia parca parca. Thus, the age of the studied deposits is Late Santonian -?Early Campanian.

Sedimentary deposition of Bozeş Formation (Apuseni Mts., Romania) - detrital zircon dating and micropaleontological ages

“…3000m-thick, turbidite-type sediments as grey sandstones and silty marls, with fine-grained conglomeratic levels in the upper part (Dimian and Popa-Dimian, 1964). Based on macroand microfauna, the age of the formation was considered Santonian -Campanian -Early Maastrichtian (Macovei and Atanasiu, 1934;Dimian and Popa-Dimian, 1964;Tomescu et al, 1969;Marincaş and Mânecan, 1971;Marincaş, 1973;Bălc et al, 2007Bălc et al, , 2012.…”

Geochemistry of Upper Cretaceous of the Bozeş Formation (Apuseni Mts., Romania) – provenance implications

“…The Bozeº For ma tion crops out in the south east ern part of the Apuseni Mts., and is rep re sented by a Santonian-Campanian turbidite-type sed i men tary se quence, con sisting mainly of grey sand stones and silty marls, with microconglomeratic lev els in the up per part and hav ing an es ti mated thick ness of 3000 m (Dimian and Popa-Dimian, 1964;Tomescu et al, 1969;Marincaº and Mânecan, 1971;Marincaº, 1973;Bãlc et al, 2007Bãlc et al, , 2012. The Bozeº For ma tion is con sid ered as a part of the West ern Transylvanides in the Apuseni Mts.…”